# Questions tagged [key-distribution]

In symmetric-key cryptography, both parties must possess a secret key that they must exchange prior to using any encryption. Distribution of secret keys is problematic: it involves face-to-face meetings, the use of a trusted courier, or sending the key through an existing encryption channel.

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### How to generate Multiple Encryption Keys for use in RSA polymorphic multiplication

I am a long time scroller, first time poster in the crypto stack. I've recently been finding myself leaving the realm of mainstream/standard crypto (imo that consists of symmetric/asymmetric ...
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### Difference between group key agreement, group key sharing, group key distribution and group key establishement

I am currently doing a survey on group key, and throughout my readings, I stumbled on these different terms: Group Key agreement, Group key Sharing, Group key distribution, and Group key establishment....
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### Why is it difficult to encrypt large amounts of information using quantum key distribution?

An article last month claimed that Toshiba Corp. and Tohoku University recently broke the record for the amount of data encrypted using quantum key distribution by transmitting "a few hundred ...
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### Compute shared public keys

I want to compute, in a distributed way, the following shared public keys on an elliptic curve: $(xG, x^2G,...,x^nG)$, being $x$ a secret scalar that no single party knows, $G$ the public ...
169 views

### One Time Pad Key Distribution

For multiple OTP keys, why not do this: Key = Hash[(EC)DH Shared Secret + Counter] The counter will increase per message, and the output of the hash will be random for each new unique input into it. ...
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### How to go about distributed private/public key pair generation?

I'm trying to implement a protocol in which two parties generate a private/public keypair, where both know the public key, but each party has only one part of the private key and cannot derive the ...
230 views

### Struggling to understand Perfect Forward Secrecy

From the definition on Wikipedia: In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key agreement protocols that gives assurances that ...
339 views

### Why Nonces and timestamps are used in Public key authority?

why the nonces(N1 and N2) and Timestamps(T1 and T2) are used in Public key Authority? which of them prevent replay attack?
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### Decentralized / Distributed Private Key Generation between Untrusted Parties?

I found an interesting concept in this paper, page 13, (Link to the paper) called "Decentralized private key generation", as follows: "Decentralized private key generation ā Multiple Enigma nodes ...
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### Protocol that generates keys every 2 minutes using KDC

I am using a Key Distributed Center (KDC) and a key distribution protocol such as Kerberos. In order to limit the amount of ciphertext produced with the same key, I want to renew the session keys ...
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### Confirmation signature - Improved Feldman VSS

I am working through the implementation of A Distributed Private-Key Generator for Identity-Based Cryptography. In the paper (Figure 1, page 8) the validation of a share by a node says that once ...
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### Reduction from integer factoring to computational Diffie Hellman

The computational Diffie Hellman (CDH) problem for ${\mathbb{Z}}^*_p$ is given a prime $p$, a generator $g$ of ${\mathbb{Z}}^*_p$, and a pair $(g^i, g^j)$ to compute $g^{ij}$. The value $g$ is called ...
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### Is E91 safer than BBM92?

I would like to compare the security of these two QKD protocols which both use entangled photons that are distributed between the users Alice and Bob. In the case of E91, the photon is measured ...
286 views

### Why is this voting system not secure?

Why not have each person simply treated as a counterparty to an off-the-record chat? People show up in groups and show an ID which is cross-referenced against a central database to prevent Sybil ...
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### Implement the joint-feldman DKG algorithm

I am looking for a work implementation of joint-feldman DKG or at least some library that can help me in the implementation Anyone can help me?
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### Understanding Quantum Key Distribution

I have watched dozens of videos on YouTube talking about Quantum Cryptography and how the BB84 algorithm works. However none of them bothered himself to explain how quantum key exchange process works ...
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### Does an EC signature preserve entropy?

Assume I have a perfect source of entropy, which is unknown to me, and is used to generate a private key (also unknown to me, but usable). If I make a signature with this unknown private key on a ...
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### Why in one time pad must the key distribution to be truly random

One time pad required a truly random key. Why canwt it be a psudo-random key? For example, if the key distribution is that for each bit the probability to get 1 is 0.6 and the probability to get 0 is ...
311 views

### Multi party anonymous key distribution

Consider a protocol, wherein Alice wants to send a message $M$ to many friends $F_1, F_2, \dots F_n$, from whom she has (some form of) public keys ($e_{F_i}$, with private key $d_{F_i}$). She does not ...
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### What makes Quantum Cryptography secure?

This is my current understanding of how Quantum Cryptography works: (The first bit is Quantum Key Distribution) Alice sends a beam of photons to Bob through a quantum channel such as an optical fiber....
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### Key Exchange & key Distribution in symmetric key cryptography

I want to know whether there is a difference between key exchange & key distribution in private key cryptography as well as public key cryptography? or is it the same term?
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### Number of uniform n-bit strings

In the set of 2^n binary strings on n-bits, how many strings have exactly equal number of 0s and 1s.
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### ABE Cryptography - Send user private key

I am studying Attribute Based Encryption. Now my study concerns CP-ABE scheme. The authority make users private keys using attributes and a Master Secret Key (of Authority). How can the authority send ...
1k views

### Key Distribution vs Key Management?

What exactly is the difference between "Key Distribution" and "Key Management"?
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### How does the sender obtain the receiver's public key?

Cryptography process includes encryption and decryption process. In public key cryptography public key of receiver is being used for encryption. I want to know how public key of receiver is sent to ...
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### Dividing a secret into multiple nodes in a blockchain kind of system with time-release?

I would like to have these features and want to ask if it is theoretically possible: a) There is custom software running on nodes in a blockchain style b) A secret is kept in the blockchain that ...
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### Security or not in Key distribution

For example, There are 3 clients. I want to deliver specific value $x$ to all clients. $x\leftarrow {0,1,2,...,q-1}$ where q is a large prime number. By using function $f(x)=x*y_{i}*z_{i}$ where i=...
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### How does Blom's scheme work?

How does Blom's scheme work? Is the polynomial expression of it a normal one? A few additional questions: How big does the prime modulus need to be? Can it be bigger than the size of the derived key?...
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### Possible to generate a one time secret which all nodes on the distributed network can know but cannot pre compute

I have a distributed P2P network. Everyday, I want each node to have a secret which is only valid for that day, while each of the other remaining nodes on the network will be able to calculate the ...
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### What are the current known weaknesses/attacks on quantum key distribution?

I am writing a paper on the implementation of QKD in the future. I want to know if there are any viable attacks on the BB84 protocol or QKD in general? I know of the Photon Number Splitting attack or ...
191 views

### One time pad ciphers in emails

In order to achieve very high security for privacy, would it be cryptographically secure to use one time pad ciphers in emails? The distribution of the keyword would pose no problems since I would ...
272 views

### How are one-time pads distributed?

It seems that OTP encryption is unbreakable. I have read some articles (Wikipedia, Blogpost, etc.), but I could not find any information about how they are used. If I wanted to create a messenger ...
1k views

### Is Pseudo-Random Generator (PRG) in OpenSSL uniformly distributed?

I need to know can we use PRG of OpenSSL as a PRF?
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### Problem in understanding Blakley's Secret Sharing Scheme

I need to implement Blakley's Secret Sharing Scheme. I have read below mentioned two research papers but still unable to understand how to implement it. Safeguarding cryptographic keys Two Matrices ...